1. Technical Field
The present invention relates to a disk chucking apparatus.
2. Description of the Related Art
Generally, in spindle motors for rotating optical recording media, such as optical disks, hard disks, etc., at high speed, an oil film is formed between a bearing and a rotating shaft using a lubricant to rotatably support the rotating shaft. Thus, high quality rotational characteristics can be ensured. Hereby, the spindle motors are widely used as a drive means for recording media, such as hard disk drives, optical disk drives, etc., which require high speed rotation.
In relation to such a spindle motor, a disk chucking apparatus holds a disk which is rotated in one direction by the rotating force of the spindle motor. The performance of the disk chucking apparatus is a very important factor in reliable rotation of the disk and alignment of the center of the disk with the center of rotation.
In other words, the disk chucking apparatus must be able to prevent the optical recording media from slipping or becoming dislodged when the spindle motor rotates at high speed and facilitate mounting/removal of the optical recording media without damaging the optical recording media or requiring excessive force. FIG. 1 is a partial sectional view of a spindle motor 20 having a disk chucking apparatus 10 according to a conventional technique which is for achieving the above purposes. FIG. 2 is a plan view of the disk chucking apparatus 10 of FIG. 1.
As shown in FIGS. 1 and 2, the disk chucking apparatus 10 according to the conventional technique includes a chuck base 12 which is provided on an upper surface of a rotor 20b which has a magnet 25 interacting with a stator 20a of the spindle motor 20. The chuck base 12 is inserted into a center hole of a disk. Seating slots 12a which radially extend predetermined lengths are formed in the upper surface of the chuck base 12 at positions spaced apart from each other along the periphery of the chuck base 12.
A chuck pin 13 is provided in each seating slot 12a so as to be movable along the seating slot 12a. The chuck pin 13 is biased outwards by elastic force of a spring 15. Elastic pieces 14 are provided in the chuck base 12 between the seating slots 12a. The elastic pieces 14 elastically support, using their own elastic force, the disk which is fitted over the chuck base 12.
In FIGS. 1 and 2, reference numeral 16 denotes a slip prevention member 16 which comes into contact with the lower surface of the disk. Reference numeral 23 denotes a holder for holding the stator 20a. Reference numeral 26 denotes a shaft which supports rotation of the rotor 20b with respect to the stator 20a. Reference numeral 27 denotes a bearing.
A process of mounting the disk to the rotor 20b using the disk chucking apparatus 10 according to the conventional technique having the above-mentioned construction will be explained. In the disk chucking apparatus 10, the outer diameter of the chuck base 12 is smaller than the inner diameter of the center hole of the disk, but the outer ends of the chuck pins 13 which are installed in the chuck base 12 radially protrude outwards from the chuck base 12. Therefore, when the disk is pushed vertically downwards above the chuck base 12, the lower edge of the circumferential inner surface of the center hole of the disk comes into contact with the chuck pins 13.
Each chuck pin 13 has a tapered structure such that the outer end of the upper surface thereof is gently inclined downwards. Thus, when the disk is fitted over the disk chucking apparatus 10, the chuck pins 13 are pushed inwards by the force of pushing the disk downwards and compress the corresponding springs 15. Simultaneously, the elastic pieces 14 are also pushed inwards and elastically deformed.
Thereafter, when the disk comes into contact with the annular slip prevention member 16 which is attached on the upper surface of the rotor 20b, the chuck pins 13 are returned to their original positions by elastic restoring force of the springs 15 which have been compressed. Thereby, the disk can be retained in the state of having been fitted over the chuck base 12, thus completing the chucking of the disk.
However, in the conventional disk chucking apparatus 10, because the separate chuck pins 13 are movably installed in the chuck base 12 and the springs 15 are interposed between the chuck base 12 and the chuck pins 13, the structure of the disk chucking apparatus 10 is complicated. Furthermore, the chuck pins 13 must be manufactured through separate processes. It is not easy to assemble the chuck pins 13 with the chuck base 12.